PEOFESSOE OWEN ON THE FOSSIL MAMMALS OF AUSTEALIA. 
199 
in the lower molars of the present species. The vertical indent (Plate 19. fig. 1, m a) 
on the inner fore part of the crown, leading to the better developed inner part of the 
prebasal ridge, is deeper than in m i, and causes a concave contour of the anterior 
enamel-border of the fore lobe. 
The mid link projects from the middle of the hind enamel-border of that lobe, 
touches, but is not continuous with, the hind part of the link sent off from the outer 
side of the fore part of the hind lobe. The vertical prominence from the corresponding- 
part of the crown of the lower molars in Nototherium is the homologue of this part of 
the mid link in Palorchestes. 
The inner concave part of the fore surface of the hind lobe shows two fine vertical 
fissures in m 2. From the low link at the back of the hind lobe the postbasal ridge 
sinks toward the base, thicker and shorter on the inner than on the outer side. The 
fore-and-aft extent of m 2 is 1 inch 1-| line (29 millims.) ; the transverse breadth of the 
hind lobe is 8^ lines (18 millims.). Here the lower penultimate molar is longer in 
the first diameter by 1 line than the corresponding tooth above, the breadth being 
the same. 
The breadth of the fore lobe of m 3 (ib. fig. 2) is 9 lines ; the length of the crown, if 
entire, would seem to have been, as in the perfect tooth in figure 4, 1 inch 2 lines, or 
1 line longer than the corresponding molar above. The proportions of the upper and 
lower last two molars in Macropus Titan are repeated in Palorchestes Azael. 
The fracture of the molar (in 3, in situ ) in figs. 1 & 2 shows the continuous part of 
the mid link to be 3 lines in vertical extent, the whole height of the link being 5 lines 
where it rises from the valley (fig. 3, r). The exposed hind root of this molar curves 
outward as it descends, and is bifurcated at the extremity. Beneath it the fracture 
shows the dental canal (fig. 3). The inner bar in m 3, as in m 2, is feebly marked at 
the inner entry of the valley (fig. 4). 
The enamel near the base of the crown and at parts of the outer surface shows, as in 
the upper molars, the fine rugse and punctations like those in the molars of Nototherium 
and Piprotodon ; and the generic pattern of the molars of Palorchestes among the 
Macropodidce indicates a transitional condition between the Kangaroos and those more 
gigantic extinct Marsupials. 
The outer surface of the mandibular ramus of the species, for which grounds are 
above assigned to justify its reference to Palorchestes Azael, shows a vascular or 
nervous outlet some way below the interval between m 1 and m 2 ; but this may be 
an individual and inconstant character. 
The depth of the horizontal ramus being given in fig. 1, I have restored the entire 
skull in outline (Plate 20), with a finished view of the left side of the original and still 
unique fossil, not figured in my former Memoir. 
§ 3. Palorchestes (Sacrum). — From the same formation in Darling Downs, Queensland, 
I have received portions of the pelvis and of the hind limbs with macropodal characters, 
and of a size corresponding with that of the above-described portions of mandible. 
